1. Field of the Invention
This invention concerns transducers, in general, and more specifically relates to improved structure for an ultrasonic transducer. In the field of measuring and testing, use is often made of ultrasonic acoustic energy in order to test thickness of a material by a reflection procedure. In such procedure electrical energy is transformed into an acoustic pulse, and such acoustic energy is then reflected from the surfaces of the material to be tested. Such a transducer may be employed in connection with testing thickness of the walls of a pipe which carries a liquid.
2. Description of the Prior Art
Heretofore, transducers for use in the above indicated field have had the drawback that the pulse of acoustic energy which is produced is lacking in short time duration characteristics. A principal aspect of this drawback relates to the mounting for the piezoelectric crystal which produces the acoustic pulse. It has heretofore been difficult to minimize the ringing effects that develop from the backing portion of the crystal mounting. Of course, more recent piezoelectric crystal material that has increased sensitivity, makes the problem worse.
Because of the difficulties with ringing effects, the determination of thickness of pipes or the like is limited by the duration of the first reflected pulse which may last too long and interfere with the second reflection pulse that follows thereafter.
Consequently, it is an object of this invention to provide a superior transducer for use with ultrasonic applications. Such transducer employs a lead metaniobate crystal with backing support that is superior to known combinations and consequently provides sharper acoustic pulses.